An internal-combustion engine obtains its power from heat and pressure produced by the combustion of a fuel-air mixture inside a closed chamber or cylinder. A spark ignition internal combustion engine, i.e., a typical gasoline engine, uses a spark to ignite the fuel-air mixture. An ignition system of a spark ignition internal combustion engine typically includes a battery, a distributor, an ignition switch, primary and secondary wiring, spark plug wires, and spark plugs. The distributor distributes an igniting voltage to the spark plugs via the spark plug wires so that they fire in a definite sequence. The spark plugs are threaded into the cylinders of a multi-cylinder internal-combustion engine to ignite the fuel-air mixture by producing timed sparks between electrodes in response to the received igniting voltage.
The spark plug wires are typically routed around or over the exhaust manifold, or header, of the internal combustion engine. A wire loom or spark plug wire retaining clips may be used to route and retain the spark plug wires. In addition, heat shields may be used to insulate the spark plug wires from the heat produced by the internal combustion engine. In a typical gasoline powered internal-combustion engine, such as in a car, van, or truck, the spark plug wires are often subject to premature failure caused by heat fatigue from the heat produced at the exhaust manifold. The problem of heat fatigue may be exacerbated if the spark plug wires become disengaged from the wire loom and come into contact with the engine. Alternatively, or in addition to heat fatigue, if the spark plug wires are incorrectly routed or become disengaged from the wire loom or retaining clips, the spark plug wires could be cut or chafed, further leading to spark plug wire failure.
Unfortunately, failure of the spark plug wires delays or prevents the igniting voltage from reaching the spark plugs, necessitating the replacement of the failed spark plug wires. Consequently, failure of the spark plug wires leads to engine malfunction, inconvenience to the owner of vehicle, and undesirable repair costs.
The replacement of failed spark plug wires can present additional problems. In particular, spark plug wire routings must be kept intact during service and followed exactly when replacement of the wires becomes necessary. Failure to route the wires properly can lead to radio ignition noise and crossfiring of the spark plugs, or shorting of the spark plug leads to ground.
Another problem arise when installing the spark plug wire boots onto the spark plugs because it may be difficult to assure that the metal terminal within the boot is fully seated on the spark plug terminal and that the boot has not moved on the wire. If boot to wire movement has occurred, the boot may give a false impression of being fully seated, although good electrical contact has not been made between the spark plug wire and the spark plug. The aforementioned conditions result in the further need for troubleshooting to identify the installation problem, increases repair time, and increases repair costs.